Searching for binary black hole mergers with deep learning in Advanced LIGO's third observing run

TL;DR

This paper introduces a hybrid deep learning and matched filtering pipeline for detecting binary black hole mergers in LIGO data, demonstrating comparable sensitivity to existing methods and identifying new gravitational wave candidates.

Contribution

The study presents a novel hybrid search approach combining deep learning with traditional methods, improving candidate detection and identifying previously unreported events in LIGO's third observing run.

Findings

Hybrid pipeline achieves comparable sensitivity for high-mass signals

Identified 31 known candidates with high probability of astrophysical origin

Discovered a new promising candidate with high chirp mass and potential intermediate-mass black hole

Abstract

The detection of gravitational waves from compact binary coalescences has provided significant insights into our Universe, and the discovery of new and unique gravitational wave candidates from independent searches remains an ongoing field of research. In this work, we built a hybrid search pipeline that combines matched filtering and deep learning to identify stellar-mass binary black hole candidates from detector strain data. We first present results from a targeted injection study to benchmark the sensitivity of our method and compare it with existing search pipelines. We demonstrate that our hybrid approach has comparable sensitivity for injections with a source-frame chirp mass greater than 25$\,$M$_{\odot}$, and below this threshold our sensitivity drops off for signals with a network SNR less than 15. We also observe that our search method can identify a significant population of unique candidates. Furthermore, we conduct an offline search for gravitational wave candidates in the third observing run of the LIGO-Virgo-KAGRA Collaboration (LVK), yielding 31 candidates previously reported by the LVK with a probability of astrophysical origin $p_{\rm astro}\geq0.5$. We identify two other candidates: one previously reported only in a search conducted by the Institute for Advanced Study, and one previously unreported promising new candidate with a $p_{\rm astro}$ of 0.63. This unique candidate has a high chirp mass and a high probability that the primary black hole is an intermediate-mass black hole.